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Study Information
Study Attribute Value
CEBS Accession Number: 002-02062-0002-0000-4
Chemical Name: Dimethyl hydrogen phosphite
CASRN: 868-85-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 601658_CA
Study Result: Positive

Study Result: Positive
Activation Trial Trial Call
No Activation  1  Weakly Positive* 
Induced Rat Liver S9  1_S9  Negative 
No Activation  2  Weakly Positive 
Induced Rat Liver S9  2_S9  Weakly Positive* 

Trial #:1   Activation: No Activation    Date: 07/11/1983    Harvest Time: 12 hour(s)   Trial Call: Weakly Positive*   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Medium 
0         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0
Test Chemical: Dimethyl hydrogen phosphite 
50         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
160         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
500         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
1600         
 100 11 0.110 10.0 7 0.070 6.0 4 0.040 4.0 0 0.000 0.0 
5000         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.25      
 100 34 0.340 24.0 17 0.170 17.0 16 0.160 14.0 1 0.010 1.0
Trend: 3.885 3.489 1.910  
Probability: 0.000 0.000 0.028  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 07/11/1983    Harvest Time: 12 hour(s)   Trial Call: Negative   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0
Medium 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Dimethyl hydrogen phosphite 
16         
 100 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0 
50         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0 
160         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
500         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
1600         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
5000         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
50         
 100 61 0.610 38.0 36 0.360 22.0 25 0.250 22.0 0 0.000 0.0
Trend: -0.832 -0.878 -0.298  
Probability: 0.797 0.810 0.617  


Trial #:2   Activation: No Activation    Date: 08/16/1983    Harvest Time: 12.8 hour(s)   Trial Call: Weakly Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Medium 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Dimethyl hydrogen phosphite 
500         
 100 2 0.020 2.0 0 0.000 0.0 2 0.020 2.0 0 0.000 0.0 
1000         
 100 3 0.030 3.0 1 0.010 1.0 2 0.020 2.0 0 0.000 0.0 
1600         
 50 7 0.140 10.0 3 0.060 6.0 4 0.080 4.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.5       
 100 50 0.500 37.0 21 0.210 19.0 29 0.290 23.0 0 0.000 0.0
Trend: 3.047 2.737 1.669  
Probability: 0.001 0.003 0.048  


Trial #:2_S9   Activation: Induced Rat Liver S9    Date: 08/16/1983    Harvest Time: 12 hour(s)   Trial Call: Weakly Positive*   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0
Medium 
0         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0
Test Chemical: Dimethyl hydrogen phosphite 
1600         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
3000         
 100 4 0.040 3.0 1 0.010 1.0 3 0.030 2.0 0 0.000 0.0 
4000         
 100 4 0.040 3.0 2 0.020 1.0 2 0.020 2.0 0 0.000 0.0 
5000         
 100 60 0.600 44.0 28 0.280 20.0 32 0.320 26.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
50         
 100 117 1.170 63.0 67 0.670 43.0 46 0.460 36.0 4 0.040 4.0
Trend: 8.029 5.445 5.889  
Probability: 0.000 0.000 0.000